Electrical fuse.



T. W. KIRKMAN.

ELECTRICAL FUSE. APPLICATION' msn JUNE 6. |915.

Patentd Aug. 14, 1917.

5 noem/07,

PATENT GFFICE.

THOMAS W. KIRKIMLAN, GF NEVI YQBK, N. Y.

Leanser.

A.Application i'iied June 6, 191.

To all ywhom it "may concern:

Be it known that L'Tioims ill/T. l? fr a citizenof the United States, re New Yori: city, in the county of New and State of New York, have invented certain new and useful improvements in tric'al Fuses, oi which the following is a specication.

il his invention relates to the construction oi: electrical fuses and especially those of the larger 'sizes employing flat copper 'terminals or electrodes. It has heretofore been-a dithcult matter to provide an inexpensive and efficient form of connection between. the casing and the terminals, principally on account of the diiiicult-y of drilling and screwthreading copper, andit is the principal object of my invention to provide a fuse which will avoid the necessityof performing either or both oi these operations. l

Of the accompanying drawings,

Figure 1 represents a longitudinal section of an electrical fuse device embodying my improvements and constructed as a reillable fuse.

Fig. 2 represents a se of Fig. 1.

Fig. 3 represents of Fig. 1.

Fig. 4f represents an'edge view ot a modiiied form of fuse terminal.

Fig. 5 represents a section on of Fig. 4.

Fig. 6 represents an edge view or a second tion on the line 22 a section on the line 33 the line :5v-5

`modiiication- Fig. 7 represents an edge view, partly in section, of a third modification, which is of the non-reiillable type.

Fig. 8 represents an inner-end view of the 'form shown in Fig. 7. 1

Referring at iirst to Figs. ,1, 2, and E, 1 indicates the cylindrical tubular casing o; vulcanized liber having sheet-metal caps 11., 11 on its ends to retain the powdered filling material (not shown) and to form apart of the connection between the casingv and the terminals, these caps being perforated at 1Q -to permit the escape of gases, and diametri cally slotted at 13 .to admit the passage ot thel copper terminals or electrodes 14.

Each electrode in this i'orm oi my invenj tion is 'madeup of a pair or" plates riveted together at 15 near their outer e ls and separated at their inner ends to receiie between them the end oi' the inse strip 16 which may beof ary suitable character, the

` Specification of Letters Patent.

Patented Auk. 14, 1917.

Serial No. l.01,903.

linse strip being secured to the Aelectrode fla-tes by a bolt 1T, which permits the fuse strip to be renewed by the -user. i

,18 are attaching, screws having screwthreaded engagement with holes in the casing 10, and passing loosely through holes in the metal caps 11, said screws at their inner ends engaging the copper terminals ,14: and serving detachably to connect said terminals with the caps and casino'. The stems of the screws occupy recesses or niches 19 at opposite points on the margins of the electrodes i4., each recess being formed by punching out a piece from one of the electrode plates and bending the wall ofthe adjacent plate, as indicated at 20, by suitable dieing operations performed in a press.

The engagement of the terminal 1st with the sides of the slot 13 in cap 11 prevents relative rotation oi said cap and terminal,

and the screws 18 preventrelative rotation as well as longitudinal movement of the cap 11 and casing 10. The terminal 14 is accordingly prevented from rotating with respect to the casing., and it is also prevented from moving longitudinally with respectthereto by reason 'of the occupation of the recesses 19 by the screws 18. The terminal is turthermore prevented by the screws Jfrom swinging or tilting on the edges of slot 13, it being noted spectivemargins are locatedk on opposite sides ci the terminal so as to prevent this action in both directions. l thus provide an etective means of detachably and securely connecting all of the parts and avoid the expensive operations of drilling and tapping the copper terminals, or attaching the latter to the casing by means of various devices of a less simple nature than the present expedient. Ordinarily no tapping of the screw-holes in the casing 10 is required, as the screws will form their own threads in the relatively-soft material of the casing.

rElie modiiication shown in Figs. i and 5 consists-in bending double a single strip or' copper toi-ming the electrode 14n. and offsetting both plates or this electrode to make circular recesses or holes 19ZL for the reception of the attaching screws.

Fig. 6 differs from Figs. l and 5 in that one of the plates is punched through on each margin of the electrode. forming a recess 19 of the same character as in Figs. l. und

lFigs. I and 8k show a modification in that the offsets 2O on the rewhich' the electrode consists' of a single strip of copper provided with olfsets 20 forming lrecess 19h for the screws,-z1nd also provided With enolfset at :2l in which the. end of a bundle of fuse Wires 22 is soldered, this `form being less adapted than the others to be refilledy by the user.

Various other modifications may heinade Within the scope of my invention.

I claim,

1. An electrical fuse device comprising L tubular casing, :t cap on the end thereof, an elec-trede in the end of said casing, hat# ing an oliset forming a recess, :1nd an attaching member connecting said parts together and occupying said recess.

2. An Aelectrical fuse device comprising n tubular casing, n. cap on the end thereof formed with :i diametrical slotend oppositely-located holes, a pair of screws thread ed in vholes in seidY casing and passing through the holes in said cap, and a. copper electrode traversing the slot in said cap and oppositely offset on its margins to form tubular casing,

recesses occupiedV by the inner ends of the screws.

3. An electrical fuse device comprisinga. tubular casing, a diemetrically-slotted cap on the end thereof, a Het electrode'occupy# ing the slot in said cap, and means connecting said members and locking the elect-rode against movement with respect to the casing in all. directions, the casing having inwardly-projecting means and the electrodes being laterally offset to provide seid connectiug means.

.1 -An electrical fuse device comprising a e cap thereon, a pair of copperplates in the end of said casing forn'ung an electrode and held from rotation with respect to said cap, said electrode lmving its margin offset to form a recess, a screw connecting the cap and casing and occupying said recess, and a fuse strip detachably clamped between said electrode plates.

In testimony whereof I have hereunto set my hand this third day of June, 1916.

THOMAS W. KIRKMAN. 

